Electric-heating-element-controlling device



- P. M. MUELLER. ELECTRIC HEATING ELEMENT coumouma DEVICE.

- APPLICATION FILED MAR. 24, 1920 RENEWED AP 1,395,003.

Patented Oct. 25, 1921 INVE N TOR m7zwzzy/ UNITED STATES PATENT OFFICE.

PAUL M. MUELLER, OF HARTFORD, CONNECTICUT, ASSIGNOR TO AMERICAN STEEL LIZER COMPANY, OF ERIE, PENNSYLVANIA, A CORPORATION OF PENLTSYLVANIA.

ELECTBIG-HEATING-ELEMENT-CONTROLLING DEVICE.

Specification of Letters Patent.

Application filed March 24, 1920, Serial No. 368,247. Renewed April 22, 1921. Serial No. 463,574.

To all whom it may concern Be it known that 1, PAUL MANNING MUEL- LER, a citizen of the United States, residing at Hartford, in the county of .Hartford and State of-Connecticut, have invented new and useful Improvements in Electric-Heating- Element-Controlling Devices, of which the following is a specification.

The object of this invention is to control the current leadingto an electric heater so as to protect the heater when it is subjected to excess heat. It is particularly desirable where the electric heater is used in connection with the receptacle for heating the liquid carried by the receptacle. Under such conditions the liquid readily difiuses the'heat and if the heating element is uncovered by'the movement of the liquid it ordinarily overheats and is thus injured. It is also desirable to have the controlling device such that it will operate under normal conditions so as to control the receptacle within certain degrees of heat.

The invention is illustrated in the'accompanying drawings as follows Figure 1 is a central vertical section of the heater with a receptacle.

Fig. 2 is a section on the line 2-2 in Fig. 1.

1 marks the receptacle for holding the liquid, and 2 a heating element extending upwardly from the bottom of the receptacle. The heating element may be of any wellknown construction and ordinarily is inclosed in a water-proof casing andthe unit as a whole involves a downward projection in which the heating element 2 is arranged. The coils of the heating element lead to the terminals 3 and through wires 4; to the switches 5 and to the line by way of the wires 6 and 7.

The thermally sensitive control is arrangedin a fitting 8 forming a part ofthe receptacle, the "controlling mechanism eX- tending through an'opening 9 in the fitting 8. Two tubes 10 and ll'extend through a plugclosure 9 into the receptacle. Thermally sensitive elements 12 and 13 are arranged in these tubes. They are in the usual form 'ofplates made up. of metals having different expansive qualities and are secured in "the blocks 14: and 15 at the ends of the tubeslO and 11. One tube extends into contact with .theicase of the heating element 2 so that'there isa direct communication of heat from the heating element to the thermally sensitive element which responds through the blade 12. The other tube 11 with its element is preferably above the end of the heating element so'that it will be uncovered prior to the uncovering of the heating element as the liquid is withdrawn.

The ends of the blades 12 and 13 are bent at 16 and screws 17 extend through these bent ends. A lever 18 has an insulated block 19 which is adapted to engage a springactuated element 20 of a'switch. The opposing element of the switch is formed by the contact plate 22 and these plates are secured to the insulated block 23 and connected to the wires 24:. These wires extend to a circuit breaker 25 which opens the circuit to the electric heater when the switch 20-22 is closed, the circuit through the wires 2% and the switch being closed from the main wires prior to the opening of the circuit through the circuit breaker.

The switch with its insulated block 23 is mounted on a plate 26, the plate having a loop which is secured to the case 9* extending fromthe plug 9. Ascrew 28 is provided by means of which the plate 26 may be moved so as to position the switch with relation to the lever 18 to be operated at a predetermined temperature or a predetermined movement of the thermally sensitive element.

In the operation of the device the difference in movement of the thermally sensitive elements 12 and 13 swingsthe lever 18 so .as to close the switch, for instance when the thermal elements are uncovered the one adj acent to the heating element 2 is subjected to a higher temperature than the blade 13 and consequently operates in advance of it. The screw on the blade 13, therefore, operates as a fulcrum on which the lever swings under the influence of the blade 12 so as to close theswitch.

here'it is desired to control the temperature where both the thermal tubes are immersed the parallel movement of the plates will effect a movement of the lever so as to operate the switch. If, however, it is desired to adjust this for this condition this may be accomplished through the action of a screw 29 which is arranged in the path of the end of the lever opposite the block 19. Vhen the lever contacts the screw 29, the screw 29 then operates as a fulcrum on which the lever swings so that with a less deflection of the plate 12 the switch 2022 will be closed. In this way the temperatures under different conditions at which the switch will be closed may be adjusted as desired.

While I have shown the heating element and receptacle in a vertical position it will be understood that this will operate with these parts in a horizontal position. One of the main advantages accomplished by this device is that through the differential action of the two heating elements the operation of the device when the heating element is uncovered is so rapid as to nearly obviate the time lag. This is a very desirable feature in this respect andrit will be observed that even what time lag there is may be controlled by lengthening or shortening the lever 18.

v WVhat I claim as new is 1. In an electric heating element controlling device, the combination of-a heating element; two thermally sensitive elements positioned relatively to the heating element to receive different degrees of heat therefrom and producing different responses under certain conditions; and a device controlled by the difference in response of the thermally sensitive elements controlling the current, of the heating element.

2. In an electric heating element controlling device, the combination of a heating element; two thermally sensitive elements positioned relatively to the heating element to receive diflerent degreesiof heat therefrom and producing different responses; a lever secured to said heat sensitive elements, said lever being swung by the difference in movement of said heat sensitive elements; and a device controlled b the lever as moved controlling thecurren to the heating element.

3. In an electric heating element controlling device, the combination of a heating element; two thermally sensitive elements positioned relatively to the heating element to receive diflerent degrees'of heat therefrom a and producing different responses under certain conditions; a lever actuated by said heat sensitive elements, said lever being swung by a difference in temperature in one element over the other and being moved by a movement of said elements together; and a device controlled by the movement of the lever controlling the current to the heating element.

4. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element in said receptacle; two' thermally sensitive elements positioned at different levels and in differing relation to the heating element; and a device controlled by said thermally sensitive elements controlling current to the heating element. I 1 7 Q I 5. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element arranged in the receptacle; two thermally sensitive elements arranged in said receptacle in differing relation to the heating element; and devices controlled by said thermally sensitive elements controlling the current to the heating element.

6. In an electric heating element controlling device, the combination ofa fluid receptacle; a heating element arranged in the receptacle; two thermally sensitive elements arranged in said receptacle in differing relation to the heating element; and devices controlled by the difference in response of said thermally sensitive elements controlling the current to the heating element.

7. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element arranged in said receptacle; two thermally sensitive elements arranged in said receptacle at different levels; and devices acting on a dif ference in movement of said thermally sensitive elements as the liquid is lowered in the receptacle controlling current to the heating element.

8. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element in the receptacle; two thermally sensitive elements arranged in the receptacle and positioned to be subjected to differing temperatures with different levels of liquid and to varying temperatures with both elements covered by liquid; and a controlling device actuated by said thermally sensitive elements operating both through a difference in movement of said thermally sensitive elements and with a common movement of said elements controlling current to the heating element;

9. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element in the receptacle; two thermally sensitive elements arrangedin the receptacle and positioned to be subjected to differing temperatures with different levels of liquid and to varying temperatures witlt both elements covered by liquid; a lever mounted on said thermally sensitive elements adapted to be swung by one on the other as a fulcrum 'whenone is subjected to a greater temperature than the other and to move the lever when. both are moved in common; and devices controlled by the movement of the lever controlling. current to the heating element. a

10. In an electric heating element controlling device, the combination of a fluid re-. ceptacle; a heating element in the 'receptacle; two thermally sensitive elements arranged in the receptacle and positioned to be subjected to differing temperatures with different levels of liquid and to varying temperatures with both elements covered by liquid; a lever mounted on said thermally sensitive elements adapted to be swung by one on the other as a fulcrum when one is subjected to a greater temperature than the other and to move the lever when both are moved in common; devices controlled by the movement of the lever controlling current to the heating element; and means for adjusting the movement ofone of the thermally sensitive elements to vary the movement of the lever through the action of said elements.

11. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element in the. receptacle; two thermally sensitive elements arranged in the receptacle and positioned to be subjected to different temperatures under different conditions, said elements comprising blades formed of metals having different expansive qualities; a lever mounted on the ends of said blades; a switch closed by said lever; and devices actuated by the switch controlling the current to the heating element.

12. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element in the receptacle; a main circuit leading to the heating element; two thermally sensitive elements arranged in the receptacle and positioned to be subjected to different temperatures under diflerent conditions, said elements comprising blades formed of metals having difi'erent expansive qualities; a lever mounted on the ends of said blades; a switch closed by said lever; and devices actuated by the switch controlling the current to the heating element comprising a shunt circuit leading to the switch; and a circuit breaker in the main circuit actuated by the shunt circuit.

13. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element in the receptacle; a plug extending through the wall of the receptacle; tubes extending through the plug and into the receptacle, one of said tubes extending to a position adjacent to the heating element; thermally sensitive elements arranged in the tubes and extending through the plug; and devices carried by the outer ends of said thermally sensitive elements controlling the current to the electric heater.

14. In an electric heating element controlling device, the combination of a fluid receptacle; a heating element in the receptacle; a plug extending through the wall of the receptacle; tubes extending through the plug and into the receptacle, one of said tubes extending to a position adjacent to the heating element; thermally sensitive ele ments arranged in the tubes and extending through the plug; a lever mounted on the outer ends of the thermally sensitive elements; and devices controlled by the lever controlling the current leading to the heating element.

15. In an electric heating element controlling device, the combination of a heating element; two thermally sensitive elements positioned relatively to the heating element to receive different degrees of heat therefrom and producing differing responses under certain conditions; a lever actuated by said thermally sensitive elements; a switch actuated by the lever; and means for adjusting the switch to and from the lever to vary the point in the movement of the thermally sensitive elements at which the switch is operated.

In testimony whereof I have hereunto set m hand.

y PAUL M. MUELLER. 

